A unique channel-type metal-organic framework (MOF) built up from mixed square-planar Co4(μ2-OH)4(μ4-OH) and cuboidal Co4(μ3-OH)4 clusters with an isonicotinic acid ligand has been successfully fabricated that demonstrates the highest specific surface area and high H2 uptake capacities among all of the cobalt(II) isonicotinic acid frameworks reported so far.